Delete winsock in Win XP SP1

Start >> Run >> Regedit
HKEY_LOCAL_MACHINE >> System >> CurrentControl >> Services
Winsock >> right click and delete.
winsock2 >> right click and delete.

Note : In Windows XP SP2 (this step is replaced by a simple command in the cmd line netsh winsock reset catalog)

Reset TCP/IP

Start >> Run >> ncpa.cpl
Right click Local Area Connection >> Properties
Select Internet Protocol >> Install (at the bottom) >> Protocol >> add >> Have Disk >> Browse >> Browse to c:\windows\inf\nettcpip >> ok
Start >> Run >> netsh int ip reset c:\resetlog.txt